CQL preflight rejects zero-slot COMFY_AUTOGROW_V3 inputs even when template min is 0

[brunocasado]

Describe the bug

comfy run rejects a valid Qwen Image 2.1 text-to-image workflow when TextEncodeQwenImage21.images has no reference images. This blocks comfy-mcp's run_workflow tool as well, because it wraps comfy run.

The ComfyUI server accepts and executes the identical API prompt through POST /prompt; only the client-side CQL preflight rejects it.

To Reproduce

Environment:

• comfy-cli 1.20.0
• ComfyUI with TextEncodeQwenImage21 available

1. Use a Qwen Image 2.1 text-to-image workflow containing this node input (with no images.* link):

{
  "452": {
    "class_type": "TextEncodeQwenImage21",
    "inputs": {
      "prompt": "a golden retriever puppy",
      "negative_prompt": "",
      "resolution": 1024,
      "clip": ["453", 0]
    }
  }
}

2. Confirm the live /object_info schema for TextEncodeQwenImage21.images declares COMFY_AUTOGROW_V3 with template.min: 0.
3. Run the complete API-format workflow:

comfy run --workflow qwen-api.json --host 127.0.0.1 --port 8188 --wait --json

Actual behavior

The CLI rejects the workflow before submitting it:

workflow_unknown_nodes
node 452: required autogrow input 'images' has no connected slots — the server will reject this node

The same prompt, submitted directly to POST /prompt, returns a prompt_id, completes successfully, and produces an image.

Expected behavior

A required autogrow input whose template declares min: 0 should be allowed to have zero expanded slots. The CLI should submit this valid text-to-image graph.

Likely fix

In comfy_cli/cql/engine.py, _check_autogrow_required() currently treats port.required as sufficient. It should also respect the autogrow lower bound, e.g. only emit autogrow_no_slots when port.autogrow_limits[0] > 0.

This preserves rejection for genuinely required autogrow inputs while allowing Qwen Image 2.1 text-to-image workflows with no reference images.

Additional context

This is not a ComfyUI server bug: the server schema explicitly permits zero images and accepts the request. It is a comfy-cli CQL preflight validation bug that manifests through comfy-mcp.

[brunocasado]

Existing fix

This is already addressed by PR #842, which fixes CQL autogrow minimum validation and explicitly handles required-section min: 0 groups with zero slots. That matches this Qwen Image 2.1 text-to-image reproduction.

No duplicate PR will be opened.